Its only for 12 Volt loads at a few hundred mA, thanks, i will take a look at this idea.
On temperature rise, a NO thermal switch would operate and provide power to the load, if that's what you want.
In order to use a NC thermal switch to provide the same function, you can use either a relay or better still a PMOS to save on idle power lost.
Connects the S(source) pin of the PMOS to +12V, its D(drain) pin to the load. Connects the NC thermal switch between its G(gate) and S pin. Then connects the G via a 22K resistor to 0V. Because of the NC nature of the thermal switch, the PMOS is cut off so no power to the load. When temperaure rises, the thermal operates and becomes open circuited. PMOS is biased and power is then fed to the load. The idle power loss is the current through the 22K resistor only.